Insects and other arthropods make up over half of all the described species on earth. Some are important as disease vectors (i.e., tsetse fly, anopheles mosquitoes, triatomine bugs, ticks ...), while many others have developed into agricultural, forest, and household pests. Chemistry plays a key role in the phyletic dominance of arthropods on earth; it is the basis for the interactions of insects with plants, with their conspecifics, with animal hosts, and with predators. The chief goal of this project is to elucidate the chemistry underlying these interactions. Insects and plants have been co-evolving for hundreds of millions of years, and the chemical relationships between these groups are rich and varied. Our work will also extend to plants in those instances where the utilization of plants toxins as insect defensive compounds and pheromone precursors seem to be important. In those instances where an insect species is dependent on plants as a source of defensive compounds, pheromones, or their precursors, the natural products chemistry of the relevant plant species will be studied. The synthesis of new insect-derived compounds showing biological activity will be an important facet of this program. This is an essential aspect of arthropod chemical research, since synthesis serves not only to confirm" structures and stereochemistry, but also supplies material in sufficient quantity for bioassays. The overall objectives of this program are: (1) to increase our understanding of natural chemical defense and communication, (2) to provide the basis for new insect control techniques which may be applicable to disease vectors of other pests, and (3) to discover new chemistry which may be useful in drug and/or agrochemical development.